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FLORA  INDICA.                                          237
Wished; and we have seen somewhat analogous instances in the growth of Fid and
Lorctnthacea and Rhizophorea, the plants of which are nourished "by adventitious
roots, having no connection with that originally developed, which has died away.
Cuscnta offers another analogous case, as do those parasites which are supposed to
be developed first on other plants, but which afterwards are nourished by terrestrial
roots. 3. The absence of a cambium-layer, of baric, pith, and of a circular arrange-
ment of vascular structures. Of these, points, the absence of pith and of the vascular
bundles forming a zone is exceptional in Victoria. The absence of a cambium-layer
is not a strong point, for there are many Exogeus in which'we have failed to trace it
iu a normal condition, and there is as much a bark in Nympliaacea as there is in a
great many other Exogeus. 4. The isolated condition of the vascular bundles. This
perhaps requires confirmation, as it appeared to ns that the bundles often united,
and, at any rate^ there are various Exogens with isolated vascular bundles both in
the pith and bark. 5. There being no analogue to wood and liber. This appears to
militate equally against their Endogenous affinity, for the vascular bundles of Endo-
gens are composed of wood and liber, while those of Nymphaacea are not; added to
which, we have seen that in Menispermea and Anstolochiea, and other Orders, the
liber is constantly absent, and iu very many Orders of Exogens the wood is wholly
replaced by vascular tissue.
Our great objection, however, to all the above arguments, is them not bearing
strongly upon the question; all appear to argue an anomalous condition of Exoge-
nous stein, none at all approach to positive indications of the-Endogenous^ and we
need hardly say, that in a case of this kind the tendency is always to magnify the
importance of small deviations from a normal type, and to seek to attach an ab-
solute value to them. Hcnfrey, however, states several objections to the Endoge-
nous iilfiuity of Fictoria, which, in au. abstract point of view, seem as unanswerable
as the arguments in favour of the same affinity, but to which we do not attach any
importance, simply because their value as physiological and structural facts is as
much unknown as that of the others. These are:—1. The vascular cord of each
root-bundle has not a central woody cylinder. 2. There is no fibrous layer between
the cortical and central substance-Si 3. The composition of the vascular bundles is
formed exclusively of ducts and unreliable spiral fibres. 4s. The frequent anastomosis
of the vascular bundles, which is not commonly the case in Monocotyledones.—To
these we may add, as of far greater weight, the arrangements of the vascular bundles
ou a longitudinal section, and that many of these run completely round the stem.
Before dismissing this difficult subject, there are two theoretical considerations
which, we think, should not be overlooked:—1, That assuming thel rhizome of Nym-
pJiffa to be that of a Dicotyledon, a consideration of its habit, development, and mode
o? growth would lead us to expect that its structure would deviate widely from the
type upon which it is formed j but that, assuming it to be a Monocotyledon, the con-
siderations in question would not lead us to expect in its rhizome 90 total a departure
from the type of that class. 2, That in a case of this kind, where the class to
which a group belongs is indicated clearly by the general structure and develop-
ment of its erobrvo, leaves, flowers, fruit, and germination, and by direct affinity with
individual members of that class, it is much more philosophical to regard au appa-
rent exception in one organ as reducible to an anomaly of the class with which the
group has a direct affinity, rather than an indication of affinity to that with which it
has otherwise bone. We hence urge, as a fatal objection to the, Endogenous affinity
of Nymph&tuca, that there is no Order amongst Monocotyledons to which T^ecnl
- or Henfrey has allied them, whilst there Are rciany aroougst Dicotyledons, with^which
they accord ia the structure of their foliage, perianth, fruit, and seed.
"We sum up our reasons for considering Nymph&acea to1 be true Dicotyledons as.
follows 's—
1.  The structure of the embryo is truly Dicotyledonous, and resembles nothing
amongst Monocotyledons.
2.  The germination is strictly Dicotyledonous and Exorhizal.  The primary leaves
are an opposite pair, alternating with the cotyledons.